Amybylopia is a developmental visual disorder, usually involving poor acuity in one eye, that affects 2% of Americans. Amybylopia has been well studied behaviorally in humans, and animal models of Amybylopia have been developed. However, little is known about the human neural substrates and mechanisms that underlie the disorder. This lack of neural characterization of amybylopia severely hinders our efforts to provide a treatment or cure. Our long-term goal is to develop a comprehensive treatment strategy for children and adults diagnosed with the two types of amybylopia, called anisometropic and strabismic. The objective of this application will be to characterize the functional anatomy of visual cortex in subjects with amblyopia, and assess the effects of a pharmacological treatment, levodopa, on visual processing, and the utility of levodopa and behavioral training as possible treatments. Our central hypothesis is that amblyopia is associated with abnormal patterns of neural activity in the visual areas of cerebral cortex, and possibly other brain regions, that are detected during specific visual tasks measured with functional magnetic resonance imaging (fMRI). The rationale for this hypothesis is that visual functions are severely degraded in amblyopia and may correlate with abnormal activation of particular visual areas. Once we characterize the pathophysiology of amybylopia we can strategically develop rehabilitation methods. Our team offers a rare combination of expertise in fMRI, clinical visual assessment, and medical treatment of eye disorders. Our methods are appropriate for describing this heterogeneous disorder because we produce detailed maps of brain activation in individual subjects. This project is innovative because we will apply a powerful, non-invasive tool to a prevalent visual impairment to create treatment regimes tailored to individual subjects. This project will also significantly advance the body of knowledge on the functional development of the immature visual system. In the future, we expect that each subjects behavior and drug treatment will be modified based on the degree to which fMRI activity patterns are normalized.